The invention relates to displaying that a cooktop surface has reached a predetermined temperature and more particularly to indicating that a stove-top cooking surface remains hot when the cooking unit has been disconnected from a power source.
Heating elements are commonly used in cooktop cooking. Alternating current power is distributed through the coils of the heating element, such as an electrically resistive heating element. The heating element then becomes hot and heats the food on the cooktop.
Many cooktops are constructed with enclosed and insulated heating elements which are disposed in a counter-top assembly below a layer of thermal glass that functions as a utensil supporting surface. Enclosing these elements prevents heat from being dissipated to the surrounding air. Further, the glass heating surface acts as a thermal barrier and retains heat for up to as much as 20 minutes after cooking has been completed. Consequently, the user may not detect that the heating surface is hot. Thus, the user may be burned by accidentally touching the glass heating surface.
Cooktops having glass cooking surfaces have been built with a display next to a control panel. These displays indicate that the cooking surface temperature is hot. However, these indicators are located away from the cooking surface and accordingly, the user may not realize that when he looks directly at the cooking surface that it is hot to the touch.
Another device that has become popular in counter-top cooking is the removable cartridge. The removable cartridge is constructed with an insulated and enclosed heating element disposed below the glass cooking surface. Accordingly, as with any glass cooktop, when the cartridge is removed, the cooking surface retains heat without any indication. Thus, the cooking surface, once removed from the counter-top, may accidentally be touched, thereby inflicting injury upon the user.